Why? Made from very hard abrasive; silicon carbide. Most other stones are aluminum oxide or ceramic, which is great for most blade alloys, but silicon carbide is much harder and therefore better suited to super steels. This G8 stone is still very suitable for simpler alloys and softer heat treated blades. ALSO, and this is important, the pores of metal shavings are easier to clean than my Shapton glass stones. I use natural Nagura stone to clean this stone but you can use a rust remover stone…